Shutdown by-pass in fuel supply for oil burner



United States Patent SHUTDUWN BY-PASS IN FUEL SUPPLY FOR OILB 1 R Armas Edvard Miettinen, Pieni Roobertinkatu 9, Helsinki, Finland Filed Nov. 5, 1362, Ser. No. 235,570 7 Claims. (Cl. l5836.3)

has reached its upper limit, and having stopped the pump forms an obstacle to the free circulation of oil in the tube system of the burner, on account of which the pump outside ofthe oil burner, e.g., in connection with the storage tank, is not able to circulate oil through the burner.

The invention is characterized in that the pipes conducting oil into the pump of the burner and out of it, or the inlet piping and the outlet piping, are connected to each other by pipes with check valves, which permit the oil to circulate past the pump eifected by outside pressure, and which connecting pipes are connected to the inlet side and the outlet side of the oil burner pump in such a way, that the pump when running seeks to create a flow of opposite direction to that permitted by the check valves, which is caused, for instance, by the pump employed in connection with the storage tank, outside of the oil burner, and which latter pump seeks to conduct the oil to the burner and from it, whereby the check valves, on account of the oppositely directed flow momentum caused by the oil burner pump, are closed and thus prevent the pump, or the like, employed with the oil tank from causin any flow in said connecting pipes.

One working example of the invention is illustrated by the enclosed drawing. FIG. 1 presents a diagrammatic View of the feeding plant of the oil burner including the attachments according to the invention, FIG. 1a shows a typical electrical circuit diagram for the solenoid valve and pump motor, and FIG. 2, a section of one check valve employed in the attachments according to the invention.

The device seen in FIG. 1 includes a so-called rotating burner H, which is designed for mounting in front of a boiler and by means of which oil is blown into the combustion chamber of said boiler. The fuel oil is kept separately in a storage tank, not seen in the drawing, in which the oil is preheated and which storage tank has its own pump, also not presented in the drawing, by means of which pump oil is forced through pipes in the direction of arrow 1 t0 the burner device 11 and from here to a first section 5-9 of burner pump 3 through tube 2, then through tube 4 to preheater 5 and from here via tube 6 to a conventional solenoid valve 7 of the modulating three-way type, from which the oil continues its path through tubes which do not show in the drawing, approximately in the direction of the arrow 8 into the combustion chamber of the boiler.

The solenoid valve 7 adjusts the amount of oil going into the combustion chamber, so that more oil is being burned at the lower heat limit of the water in the boiler, and as the temperature of the water rises from its lower limit, the solenoid valve closes its flow channels in such a way, that less oil goes into the combustion chamber in the direction of arrow 8 while part of it is returned to the storage tank in such a way, that the oil returning passes at first through tube 9 back through a second section 51 of the pump 3, and from here by way of tube it ice to the return side of the device 11 and then in the direction of arrow 12 back to the storage tank.

Conventional temperature-responsive control means are provided so that when the temperature of the water being heated in the boiler has reached its upper limit, the solenoid valve reduces the how of oil to the boiler in the direction of arrow 3 completely, .or almost completely, and the pump 3 may stop or may be stopped. .Whenthe pump 3 does not operate, the oil cannot return by way of said second. section of pump 3 to the storage tank along the above-mentioned path 9, 3, lit, l1, l2, and remains stationary in the tubes. The pump at rest also blocks the passage of oil throughtubes 2, 4, and 6.

if heavier oil, or the less mobile and more viscous oil with the trade name oil No. 4 is used, the consequence of the oil stopping in the tubes is that the pump cannot be started again. This is prevented by the heavy oil which has stiffened in the tubes and cannot be circulated by the pump 3. 7

Under such conditions, and especially during the summer, when the burner is not .in use for long periods at a time, the oil will solidify completely in. the tubes and the pump will not start. Therefore the commercial oil No. 2 is generally used during the summer because of its lower viscosity, which prevents it from stilfening in the tubes when standing still. The oil No. 2, or the so-called light oil, is much more expensive however, on 1 account of which there will be a considerable cost increase when the oilburner is used during the summer.

The aim of this invention is to get rid of the these disadvantages. In accordance with the invention tubes 2 and 6 are connected by a tube 13, which isfurnished with a check valve 14- and a needle valve l5.v Also according to the invention the tube is connected to tube ill by means of tube 3.6,WhiCh is also furnished with a check valve 17 and a needle-valve l8.

FIG. 2 presents a longitudinal section of one of the check valves 14 and 17,011 a larger scale than in FIG. 1. Situated in the valve box 19 is a ball 20, which closes the tube continuing downwards from here, so that liquid cannot how downwards through the check valve but upwards only. The upward flow of oil lifts the ball upwards and;

the oil passes the ball flowing upwards in the valve box 19.

The needle valves 15 and K8 are of a design fully known as such and when closed these valves prevent the flow of oil through them, and correspondingly, allow the oil to pass through when they are open:

When the temperature of the Water in the burner has reached its upper limit, and the burner ceases to operate as the pump stops, the check valve 14 opens as the pump of the storage tank continues to cause pressure in tube 2, the needle valve 15 being open. Then the oil is able to circulate from tube 2 to tube 6 by way of tube 13, past pump 3 and preheater 5, and onward from tube 6 by way of solenoid valve 7 to tube causing pressure at this point, so that also check valve 17 will open, and needle valve 13 being open, oil is able to flow by wayI of tube 16 to tube in, past pump 3, and from the tube Ill by way ;of

device 11 in the direction of arrow 12 into the storage t tank.

Because the storage tank has its own preheater for the Oil audits own pump, which seeks to keep the oil in the tube system moving, oil will thus circulate continuously in the above described manner from the storage tank through the oil burner aggregate, by-passing pump 3, and back to the storage tank so that the oil has no time to cool down in the tube system of the oil burner to such extent that it would hinder the starting of pump 3. Thus, when the pump 3 is starting with the waterat its lowest temperature level, the first section of pump 3 immediately causes pressure in tube 4 and suction in tube 2, at

e which the check valve 14 closes and the circulation of oil in tube 13 ceases, but instead the oil starts to circulate from tube 4 into preheater 5 and from here to tube 6. Correspondingly, the second section 51 of pump 3 upon starting causes pressure in tube and suction in tube 9, at which also the check valve 17 closes and the oil circulation in tube 16 ceases, but continues instead from tube 9 into the second section 51 of pump 3 and from here to tube 10 inasmuch as the solenoid valve allows oil to flow by way of these tubes back into the storage tank.

As shown in FIGURE la, the conventional modulating solenoid valve unit 7 may comprise a suitably ported valve rotor '70 whose position is controlled by a solenoid 71, which is energized through a rheostat '72 which is operated by a temperature-responsive element '73 located in the water tank. The temperature-responsive element 73 may likewise control a conventional switch 74 connected in the energizing circuit of the pump motor which is arranged to open when the water in the tank rises to a predetermined temperature.

It should be said in this connection that the actual object of pump 3, besides and in addition to the pump of the storage tank, is only to speed up in a suitable manner the flow of oil in the burner.

With the attachments, according to the invention, it is possible therefore to use the heavy oil No. 4 also under summer conditions. Pump 3 may thus be at a standstill for long periods of time, but the oil will circulate in the meantime through tubes 13 and 16 due to the compression of the pump of the storage tank, while being heated by the heater of same, so that the oil has no chance to freeze in the tubes of the burner and the pump 3 will start easily no matter if it has been standing still for a great length of time. After the pump has started, the circulation of oil in tubes 13 and 16 again automatically stops in the above described manner, and this causes an oppositely directed flow impulse effected by pump 3 in tubes 13 and 16.

With'the additional device, according to the invention, the cheaper heavy oil No. 4 can be used under summer conditions, which means a considerable saving in running costs.

Provided that for one reason or another one wishes to use the mobile oil No. 2, the needle valves .15 and 18 may be closed, entirely, in which case oil under no circumstances is able to circulate by way of tubes 13 and 16.

The invention is not restricted only to the above described and illustrated example performance, but it can be varied in various ways within the scope of the patent claims following.

Thus the invention can be applied also in a feeding plant of an oil burner of such a design, that the tubes 9 and 10 shown in FIGURE 1 are omitted. Naturally, this kind of a burner aggregate cannot be equipped with a tube 16 including the check valve 17 and the needle valve 18. A feeding device like the one concerned is designed to feed during its operation the oil coming from tube 6 into the solenoid valve 7 and from here entirely in the direction of arrow 8 into the oil burner, with no return of oil whatsoever through pump 3 into the storage tank.

According to the invention a feeding plant of the above design can be furnished with a connecting tube 13 including check valve 14 and needle valve 15 in the manner presented in FIG. 1, and in order to also realize the invention in a case like this, the tube 6 connecting to solenoid valve 7 is joined by means of a connecting tube to that line, not shown in FIG. 1, which conducts oil in the direction of arrow 12 back to the storage tank. The above-mentioned connecting line is joined to some point on tube 6 which lies somewhere between the solenoid valve and its connecting point with tube 13. This connecting line is also furnished with a needle valve, the opening of which is adjustable to suitable size, so that oil in a suitable amount can be allowed to flow from tube 6 by way of the connecting line back into the storage tank. The needle valve in said connecting tube can be adjusted so that it is continuously open so much, that even when the solenoid valve 7 is conducting oil in the direction of arrow 8, burner oil is at the same time also able to flow along said connection tube back into the storage tank.

When the solenoid valve 7 completely closes, and stops the passage of oil to the burner in the direction of arrow 3, the flow of oil continues from tube 6 by way of said connecting tube into the storage tank, so that oil will not obstruct the lines by cooling down. The flow of oil can thus continue also in the case that pump 3 stops, at which the oil on the incoming side flows past the pump from tube 2 by way of tube 13 to tube 6 and onward from here past the solenoid valve in the manner described above and back to the storage tank.

I claim:

1. In combination with an oil burner system of the type including a pressurized oil supply line, a preheater, a two-section pump, a three-way solenoid valve having an inlet and two outlets, means for connecting one of said outlets to a combustion chamber, first conduit means including one of said pump sections connecting said pressurized oil supply line to said preheater, second conduit means connecting the preheater to said valve inlet, and a return line connected to the other valve outlet through the second pump section; respective bypass conduits con nected between the supply line and the second conduit means and connecting said other valve outlet to the return line across the second pump section, and normally closed flow-restricting means in said bypass conduits adapted to be opend to allow continuous circulation of oil from the supply line to the return line when the pump is inoperative.

2. The structure of claim 1, and wherein said lastnamed means includes at least one check valve opening to allow flow only in the direction of said circulation.

3. The structure of claim 1, and wherein said lastnamed means comprises respective check valves in the by-pass conduits opening to allow flow only in the direction of said circulation.

4. The structure of claim 1, and wherein at least one of said by-pass conduits contains an adjusable needle valve.

5. In combination with an oil burner system of the type including a pressurized oil supply line, a preheater, means to connect the outlet of the preheater to a combustion chamber, a return line connected to the outlet of the preheater, and conduit means including a pump connecting said supply line to the inlet of the preheater; bypass conduit means connected between the supply line and the outlet of the preheater, and normally closed flowrestricting means in said by-pass conduit means adapted to be opened to allow continuous circulation of oil from the supply line to the return line when the pump is inoperative.

6. The structure of claim 5, and wherein said by-pass conduit means includes a check valve opening to allow flow only in the direction of said circulation.

7. The structure of claim 6, and wherein said by-pass conduit means also includes an adjustable needle valve.

References Cited by the Examiner UNITED STATES PATENTS 1,577,622 3/26 Gaston. 2,896,699 7/59 Rulseh 158360 2,901,031 8/59 Powell et al 158-36.4

FOREIGN PATENTS 825,048 11/37 France.

JAMES W. WESTHAVER, Primary Examiner.

FREDERICK KETTERER, Examiner. 

1. IN COMBINATION WITH AN OIL BURNER SYSTEM OF THE TYPE INCLUDING A PRESSURIZED OIL SUPPLY LINE, A PREHEATER, A TWO-SECTION PUMP, A THREE-WAY SOLENOID VALVE HAVING AN INLET AND TWO OUTLETS, MEANS FOR CONNECTING ONE OF SAID OUTLETS TO A COMBUSTION CHAMBER, FIRST CONDUIT MEANS INCLUDING ONE OF SAID PUMP SECTIONS CONNECTING SAID PRESSURIZED OIL SUPPLY LINE TO SAID PREHEATER, SECOND CONDUIT MEANS CONNECTING THE PREHEATER TO SAID VALVE INLET, AND A RETURN LINE CONNECTED TO THE OTHER VALVE OUTLET THROUGH THE SECOND PUMP SECTION; RESPECTIVE BYPASS CONDUITS CONNECTED BETWEEN THE SUPPLY LINE AND THE SECOND CONDUIT MEANS AND CONNECTING SAID OTHER VALVE OUTLET TO THE RETURN LINE ACROSS THE SECOND PUMP SECTION, AND NORMALLY CLOSED FLOW-RESTRICTING MEANS IN SAID BYPASS CONDUITS ADAPTED TO BE OPENED TO ALLOW CONTINUOUS CIRCULATION OF OIL FROM THE SUPPLY LINE TO THE RETURN LINE WHEN THE PUMP IN INOPERATIVE. 